JP6609440B2 - Mounting structure for multiple embedded bolts - Google Patents

Description

  The present invention relates to a mounting structure for a plurality of embedded bolts for embedding and fixing a plurality of bolts in a concrete layer.

  When fixing a bolt to a concrete layer, for example, a lining concrete layer of a tunnel, an anchor bolt of an extension shaft type provided with a split groove at the tip is driven into the concrete layer (for example, Patent Document 1) and embedded in the lining concrete layer. In general, a base end threaded portion in which an anchor pin adhesive is applied to an insert having a female thread cut therein is screwed (for example, Patent Document 2).

Japanese Patent Publication No. 8-19833 Japanese Patent No. 3801013

  However, the method of fixing the anchor bolt by plunging the anchor bolt into the lining concrete layer and expanding the split groove at the tip thereof, and the method of fixing the bolt to the embedded insert by the adhesive filler and screwing, It was difficult to keep the bolt fixing strength high over a long period of time. In particular, the tendency is large in the environment where vibration is applied to the fixed part or the environment is humid or humid.

  The applicant of the present application has proposed an embedded bolt mounting structure that can maintain a high fixing strength over a long period of time without being influenced by the environment. The present invention can ensure high fixing strength as a whole, particularly when a plurality of embedded bolts of this type are installed in a concrete layer, even when vibrations or external forces in a specific direction are applied to the embedded bolts. An object of the present invention is to provide a mounting structure for a plurality of embedded bolts.

  According to the present invention, the mounting structure of the plurality of embedded bolts includes a plurality of keyhole holes drilled in the concrete layer where the embedded bolts are to be installed, and a head inserted into and fixed to the plurality of keyhole holes. A plurality of embedded bolts. Each keyhole-shaped hole communicates with the first non-through hole having a diameter larger than the diameter of the head of the embedded bolt, and is smaller than the diameter of the head of the embedded bolt and is smaller than the diameter of the head of the embedded bolt. And a second non-through hole having a diameter larger than the diameter of the shaft portion and in which the head of the embedded bolt is disposed. In particular, according to the present invention, the concrete layer is a concrete layer on a ceiling surface, and at least a part of the plurality of keyhole-shaped holes is formed from the center of the first non-throughhole to the second non-throughhole. The concrete layer is perforated so that the directions to the center are different from each other.

  With respect to the concrete layer on the ceiling surface, at least some of the plurality of keyhole-shaped holes are drilled so that the directions from the center of the first non-through hole to the center of the second non-through hole are different from each other. Therefore, even when vibration or external force in a specific direction is applied to the embedded bolt, it is possible that all the embedded bolts are displaced from the second non-through hole and the pull-out strength is reduced. As a whole, a high fixing strength can be ensured.

  At least some of the plurality of keyhole holes are formed in the concrete layer such that directions from the center of the first non-through hole to the center of the second non-through hole are opposite to each other. It is preferable.

  The concrete layer is a side wall surface or a slanted wall concrete layer, and at least a part of the plurality of keyhole holes has a direction from the center of the first non-through hole to the center of the second non-through hole. It is also preferable that the concrete layer on the side wall surface or the inclined wall surface is perforated so as to be in the downward direction on the side wall surface or the inclined wall surface. With respect to the concrete layer provided on the side wall surface or the oblique wall surface, at least a part of the keyhole-shaped holes are formed in a downward direction from the center of the first non-through hole to the center of the second non-through hole. Therefore, it does not occur that the embedded bolts provided in the keyhole-shaped holes are displaced from the second non-through holes and the pull-out strength is reduced. For this reason, high fixing strength can be ensured as a whole.

  Each keyhole-shaped hole has a width substantially equal to the diameter of the second non-through hole, and communicates the second non-through hole and the first non-through hole with each other over substantially the entire length of the second non-through hole. The first non-through hole having a width substantially equal to or slightly larger than the diameter of the first non-through hole and only in a predetermined depth range of the second non-through hole. And a second lateral communication passage that allows the first non-through hole to communicate with each other, and a head of the embedded bolt is disposed in the second lateral communication passage of the second non-through hole. It is also preferable to be configured as described above. In each keyhole-shaped hole, the embedded bolt is supported by a concrete layer in the vicinity of the second non-through hole whose head is located on the surface side of the second lateral communication path. It becomes a high value according to the thickness of the concrete layer in this part, and it is maintained for a long time without being influenced by the environment. As a result, the fixing strength of the embedded bolt can be more reliably maintained over a long period of time in any environment.

  Filler is filled in the first non-through hole, the second non-through hole, the first lateral communication path, and the gap between the second lateral communication path and the embedded bolt of each keyhole-shaped hole. Is preferred.

  In each keyhole-shaped hole, it is also preferable that the first non-through hole is deeper than the depth of the second non-through hole.

  According to the present invention, even when vibration, external force, or the like in a specific direction is applied to the embedded bolt, all the embedded bolts are displaced from the second non-through holes and the pullout strength is reduced. As a whole, high fixing strength can be secured. Of course, in each keyhole-shaped hole, the embedded bolt is supported by a concrete layer in the vicinity of the second non-through hole whose head is located on the surface side. It becomes a high value according to the thickness of the layer, and is maintained for a long time without being influenced by the environment.

It is a top view which shows roughly the attachment structure of the some embedding bolt to the concrete layer of a ceiling surface as one Embodiment of this invention. It is a top view which shows roughly the attachment structure of the some embedding bolt to the concrete layer of the side wall surface or the slant wall surface in embodiment of FIG. It is a perspective view which shows roughly the attachment structure of each embedding bolt to the concrete layer in embodiment of FIG. It is a top view which shows roughly the attachment structure of each embedding bolt to the concrete layer in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. It is sectional drawing which shows the BB line cross section of FIG. It is a side view which shows roughly an example of each embedded bolt in embodiment of FIG. It is a flowchart explaining the schematic construction process in embodiment of FIG. It is a perspective view which shows an example of the inking tool used at the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is a perspective view which shows an example of the positioning jig used at the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is a perspective view which shows an example of the jig for depth determination used at the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG. It is sectional drawing which shows the AA line cross section of FIG. 4 for demonstrating the construction process in embodiment of FIG.

  FIG. 1 schematically shows a structure for attaching a plurality of embedded bolts to a concrete layer on a ceiling surface as one embodiment of the present invention, and FIG. 2 shows a side wall surface or a slant wall surface on the concrete layer in this embodiment. The attachment structure of a plurality of embedding bolts is shown roughly.

  Although this embodiment is not limited to this, For example, it is related with the structure which attaches a some embedding bolt to the lining concrete layer provided in the ceiling, the side wall, or the slant wall of the tunnel for motor vehicles or a railway. In the present embodiment, these embedded bolts are used to suspend or attach structures such as various signs, jet fans, signals, or overhead wires to the lining concrete layer.

  In FIG. 1, 1 is a lining concrete layer on the ceiling surface, 2a and 2b are a plurality of keyhole holes for bolts which are non-through holes drilled in the lining concrete layer 1, and 3 is a plurality of keyhole shapes. A plurality of embedded bolts each having its head inserted and fixed in holes 2a and 2b are shown.

  Each of the plurality of keyhole-shaped holes 2 a and 2 b communicates with the first non-through hole 4 having a diameter larger than the diameter of the head of the embedded bolt 3 and the first non-through hole 4. A second non-through hole 5 having a diameter smaller than the diameter of the head and larger than the diameter of the shaft portion of the embedded bolt 3 is provided.

  As is clear from FIG. 1, a part of the plurality of keyhole-shaped holes 2 a and 2 b and the remaining keyhole-shaped holes 2 b are formed from the center of the first non-throughhole 4 to the second non-penetrated hole. The lining concrete layer 1 on the ceiling surface is drilled so that the direction to the center of the hole 5 (hereinafter referred to as the direction of the keyhole-shaped hole) is opposite to each other. In the example shown in FIG. 1, the direction of the keyhole-shaped hole 2 a and the direction of the keyhole-shaped hole 2 b are opposite to each other. The effect of this embodiment can be obtained. However, when the angle between the different directions is closer to 180 degrees, a larger effect can be obtained, and when it is too small (for example, 5 degrees or 10 degrees of 90 degrees or less), a more effective effect is obtained. I can't. Further, the different directions do not need to be two different directions, and may be three or more different directions. Furthermore, the direction of all of the keyhole holes provided in the lining concrete layer 1 on the ceiling surface may be different from each other, and the directions of some of the keyhole holes may be different from each other.

  In FIG. 2, 1 'is a lining concrete layer of a side wall surface or a slanted wall surface, 2' is a plurality of keyhole-shaped holes for bolt attachment which are non-through holes formed in the lining concrete layer 1 '. Shows a plurality of embedded bolts each having its head inserted into and fixed to a plurality of keyhole holes 2 '.

  Each of the plurality of keyhole-shaped holes 2 'communicates with the first non-through hole 4' having a diameter larger than the diameter of the head of the embedded bolt 3 'and the first non-through hole 4'. A second non-through hole 5 ′ having a diameter smaller than the diameter of the head of 3 ′ and larger than the diameter of the shaft of the embedded bolt 3 ′ and in which the head of the embedded bolt 3 ′ is disposed. I have.

  As is clear from FIG. 2, the plurality of keyhole-shaped holes 2 ′ are formed in a direction from the center of the first non-through hole 4 ′ to the center of the second non-through-hole 5 ′ (hereinafter referred to as the direction of the keyhole-shaped hole). Is pierced in the lining concrete layer 1 'so as to be in the downward direction. Here, the downward direction is a direction (including an oblique direction) directed downward from the horizontal direction, and is not limited to a downward direction perpendicular to the horizontal direction as shown in FIG. In the example shown in FIG. 2, the direction of the keyhole-shaped hole 2 ′ is the same downward direction, but the effect of this embodiment described later can be obtained even if the directions are slightly different from each other downward. it can. Moreover, it is good also considering only the direction of the one part keyhole-shaped hole as a downward direction, without setting the direction of all the keyhole-shaped holes provided in the covering concrete layer 1 'of the side wall surface or the slant wall surface as a downward direction.

  FIG. 3 schematically shows a structure for attaching each embedded bolt to the lining concrete layer in this embodiment, FIG. 4 schematically shows each embedded bolt attachment structure in this embodiment, and FIG. 4 shows a cross section taken along line AA in FIG. 4, FIG. 6 shows a cross section taken along line BB in FIG. 4, and FIG. 7 schematically shows an example of each embedded bolt in the present embodiment.

  3 and 4, 10 is a lining concrete layer on the ceiling surface, side wall surface or slant wall surface, 11 is a keyhole-shaped hole drilled in the lining concrete layer 10, and 12 is fixed to the keyhole-shaped hole 11. Embedded bolt 13, a washer passed through embedded bolt 12, 14 a nut screwed into embedded bolt 12, and 15 a filler filled in keyhole-shaped hole 11. However, in FIG. 4, in order to clearly show the shape of the keyhole-shaped hole 11, the indication of the washer 13 and the nut 14 is omitted.

  As shown in FIGS. 4 to 6, the keyhole-shaped hole 11 includes a first non-through hole (bolt insertion hole) 16, a second non-through hole (bolt installation hole) 17, and a first lateral connection. It is mainly composed of a passage 18 and a second lateral communication passage 19.

The first non-through hole 16 is a non-through hole drilled to a predetermined depth (for example, about 80 mm) from the surface of the lining concrete layer 10, and the head of the embedded bolt 12. It has a larger diameter phi ₁ than the diameter of 12a. The second non-through hole 17 is a non-through hole drilled from the surface of the lining concrete layer 10 to a predetermined depth (which is just an example, for example, about 70 mm). 16 smaller than the diameter phi ₁ of and has a larger diameter phi ₂ than the diameter of the shaft portion 12b of the stud 12. The depth of the first non-through hole 16 is slightly deeper than the depth of the second non-through hole 17 (and the second lateral communication path 20) (about 10 mm in the above example). This is because the bottom 16a of the first non-through hole 16 (see FIG. 5 and FIG. 6) has irregularities based on the aggregate contained in the concrete when the first non-through hole 16 is drilled. This is for the purpose of matching the depth with the second non-through hole 17 and the second lateral communication path 19. By forming such irregularities on the bottom 16 a of the first non-through hole 16, the filler 15 can enter between the irregularities and increase the adhesive strength.

As the embedded bolt 12, various shapes and sizes can be used. In this embodiment, as an example, as shown in FIG. 7, it is assumed that M12 × 130 having a circular head 12a is used. Of course, the shape of the head 12a may be various shapes other than a circular shape such as a hexagonal shape, and various sizes are applicable. As in this embodiment, when M12 × 130 is used, the diameter of the head 12a is about 30 mm, the thickness is about 5 mm, and the diameter of the shaft portion 12b is about 12 mm. In this case, the diameter phi ₁ of the first non-through hole 16 is 32 mm, the diameter phi ₂ of the second non-through hole 17 is about 14 mm.

The first lateral communication passage 18 has a width W ₁ substantially equal to (or slightly larger than) the diameter φ ₂ of the second non-through hole 17, and the first transverse communication path 18 extends over the entire length of the second non-through hole 17. The two non-through holes 17 and the first non-through hole 16 are communicated with each other. The second lateral communication path 19 has a width W ₂ that is substantially equal to (or slightly larger than) the diameter φ ₁ of the first non-through hole 16 and has a predetermined depth (simply a mere distance from the surface of the lining concrete layer 10). For example, for example, about 70 mm), a predetermined depth (for example, about 6 mm when the embedded bolt 12 is M12 having a thickness of about 5 mm as described above) is used. The two non-through holes 17 and the first non-through hole 16 are communicated with each other. In other words, the second lateral communication passage 19 is provided in the depth range of about 64 to about 70 mm in this case.

  An embedded bolt 12 is installed in the second non-through hole 17 so that the end portion protrudes to the outside of the lining concrete layer 10. In that case, the head 12 a of the embedded bolt 12 is installed so as to be positioned in the second non-through hole 17 and the second lateral communication path 19.

  The gap between the first non-through hole 16, the second non-through hole 17, the first lateral communication path 18 and the second lateral communication path 19 and the embedded bolt 12 is shown in FIGS. As shown, a filler 15 such as non-shrink mortar or lightweight mortar is filled. Instead of such a filler, for example, a resin adhesive having viscosity such as an epoxy resin or an acrylic resin, or other adhesive filler having adhesiveness may be filled.

  The diameter, width, and depth of the first non-through hole 16, the second non-through hole 17, the first lateral communication path 18, and the second lateral communication path 19 are the same as the dimensions of the embedded bolt 12. It is decided accordingly. In the present embodiment, M12 × 130 is used as the embedded bolt 12, but other lengths of M12 or M14 or M16 embedded bolts may be used. However, as the embedded bolt, one having a diameter as small as possible within the allowable range from the load reduces the diameter of the second non-through hole 17. The effect of the load is reduced. Moreover, the one where the diameter or width | variety of the 1st non-through-hole 16, the 2nd non-through-hole 17, the 1st horizontal direction communication path 18, and the 2nd horizontal direction communication path 19 is smaller to the lining concrete layer 10 In addition to the small influence of the load, the size of the machining tool is reduced and the machining time is shortened.

  Hereinafter, the construction procedure in the present embodiment will be described in detail with reference to FIGS.

  First, on the surface of the lining concrete layer 10, the positions where the first non-through holes (bolt insertion holes) 16 and the second non-through holes (bolt installation holes) 17 are determined by confirming the bar arrangement positions. (Step S1). For this marking, it is efficient to use a marking tool 20 as shown in FIG. The inking jig 20 is a transparent plastic plate, and on one side thereof, vertical and horizontal reference lines 20a and 20b for defining the positions where the second non-through holes 17 are formed are described. A through hole 21 corresponding to the first non-through hole 16, the second non-through hole 17, and the first lateral communication path 18 is formed. This inking jig 20 is placed on the lining concrete layer 10 on the basis of the position of the second non-through hole 17 on the surface of the lining concrete layer 10, and the ink is drawn along the outline of the through hole 21. Make out.

  Next, using a core drill that is adsorbed and fixed to the surface of the lining concrete layer 10, the lining concrete layer 10 is drilled vertically to form a first non-through hole 16 (step S2). In the present embodiment, the first non-through hole 16 is drilled to have a depth of about 80 mm, and a columnar concrete piece corresponding to the drilled hole is formed by applying a lateral load to the drilled portion. obtain. FIG. 10 shows a state in which the first non-through hole 16 has been drilled using a core drill, and FIG. 11 shows the first non-through hole 16 in a state in which the columnar concrete piece remaining by the drilling has been removed. Show.

  Next, the lining concrete layer 10 is drilled by using a core drill or a hammer drill, and the second non-through hole 17 is formed (step S3). The second non-through hole 17 is formed so as to be shallower by about 10 mm than the first non-through hole 16 and to have a depth of about 70 mm. FIG. 12 shows a state where the second non-through hole 17 is formed.

Next, a space between the first non-through hole 16 and the second non-through hole 17 of the lining concrete layer 10 is drilled using a core drill or a hammer drill, and the diameter of the second non-through hole 17 is continuously increased. A non-through hole having the same diameter as φ ₂ is drilled. The depth of this non-through hole is about 70 mm, which is the same as that of the second non-through hole 17. In this case, it is desirable to use a metal (for example, steel) positioning jig 22 as shown in FIG. 13 for defining the drilling position of the non-through hole. This positioning jig 22 has a cross-shaped protruding portion 23 serving as a reference and a through hole 24a or 24b with a cylindrical portion for inserting a drill. By inserting the cross-shaped protruding portion 23 into the first non-through hole 16 and inserting a drill from the back side of FIG. 13 and drilling at that position, the non-through hole is easily formed at a desired position. By forming such a non-through hole, a first lateral communication is established that allows the second non-through hole 17 and the first non-through hole 16 to communicate with each other over the entire length of the second non-through hole 17. A passage 18 is formed (step S4). The width W ₁ of the first lateral communication path 18 is substantially equal to (or slightly larger than) the diameter φ _{2 of} the second non-through hole 17. FIG. 14 shows a state in which the first lateral communication path 18 is formed.

Next, using a sander drill with a special rotary blade attached to the tip of the rotary shaft, from the first non-through hole 16 in a predetermined depth range (depth range of about 64 to about 70 mm) of the lining concrete layer 10 The second lateral communication path 19 is formed by grinding in the direction of the second non-through hole 17 (step S5). Determining the depth of metal (for example, steel) as shown in FIG. 15 for translating the sander drill in order to form the second lateral communication passage 19 parallel to the surface of the lining concrete layer 10 It is desirable to use the jig 25. This depth determining jig 25 has drill mounting portions 26 and 27 for mounting the main body of the sander drill, and has a sliding surface on the back side in FIG. The main body of the sander drill is placed on the drill mounting portions 26 and 27, the rotation shaft and the rotary blade thereof are inserted into the first non-through hole 16, and the sliding surface is slid on the surface of the lining concrete layer 10. Thus, the rotary blade can be easily translated at a predetermined depth along the surface of the lining concrete layer 10. FIG. 16 shows a state in which the second lateral communication path 19 is formed. The used sander drill has a rotating shaft longer than a normal one, and the rotating blade mounted on the tip thereof has an outer diameter substantially equal to or slightly larger than the diameter φ ₁ of the first non-through hole 16. And a predetermined thickness. Thus, the formed second lateral communication passage 19 has a width substantially equal to or slightly larger than the diameter φ1 of the _first non-through hole 17, and its height corresponds to the thickness of the rotary blade ( For example, about 6 mm).

  Next, the embedded bolt 12 is installed in the second non-through hole 17 (step S6). In this installation, as shown in FIG. 17, the head 12 a of the embedded bolt 12 is inserted into the first non-through hole 16, and the inside of the first lateral communication passage 18 and the second lateral communication passage 19 is inserted. This is done by moving to the second non-through hole 17. FIG. 18 shows this state.

  After that, as shown in FIG. 19, for example, a non-shrink mortar or a lightweight mortar filler 16 is filled with the first non-through hole 17, the second non-through hole 17, the first lateral communication path 18, and the second In order to prevent a gap from being generated in all the holes including the lateral communication path 19 and the entire path, filling is performed so as not to generate a gap between the embedded bolts 12 (step S7). This filling is performed using a grease gun, a spatula and / or a trowel. The embedded bolt 12 is preferably cured with a vinyl tape or the like in a portion exposed from the surface of the lining concrete layer 10.

  Thereafter, the nut 14 is screwed into the embedded bolt 12 via the washer 13, and the embedded bolt 12 is firmly fixed. This state is shown in FIGS.

  After the filler 15 is cured, the structure is attached to the embedded bolt 12.

  As described above, according to the present embodiment, with respect to the lining concrete layer 1 on the ceiling surface, the direction of the keyhole-shaped hole 2a is drilled so as to be opposite to the direction of the keyhole-shaped hole 2b. Since the embedded bolts 3 are inserted into the non-through holes 5 of the second, even when vibrations or external forces in a specific direction are applied to the embedded bolts 3, all the embedded bolts 3 are in the second non-through holes. Therefore, it is possible to ensure a high fixing strength as a whole. Further, with respect to the lining concrete layer 1 'provided on the side wall surface or the inclined wall surface, the direction of the keyhole-shaped hole 2' is drilled downward, and the embedded bolt 3 'is inserted into the second non-through hole 5'. Therefore, the embedded bolt 3 ′ is not displaced from the second non-through hole 5 ′ and the pullout strength is not lowered, and a high fixing strength can be ensured as a whole. Of course, each of the embedded bolts 3, 3 ′, 12 has not only the filler 15 but also the second non-through holes 5, 5 ′ whose head 12 a exists on the surface side of the second lateral communication passage 19. It will be supported by the lining concrete layers 1, 1 ′ and 10 near 17. For this reason, the pull-out strength of the embedded bolts 3, 3 ', 12 is a high value corresponding to the thickness of the lining concrete layers 1, 1', 10 in this portion, and this pull-out strength depends on the environment. Not maintained for a long time. As a result, the fixing strength of the embedded bolts 3, 3 ′, 12 can be more reliably maintained over a long period of time in any environment where vibration or moisture is applied.

  Hereinafter, a bolt pull-out test of the embedded bolt mounting structure of the present invention will be described.

Table 1 shows the results of a bolt pull-out test carried out at the Tokyo Metropolitan Industrial Technology Research Center Demonstration Center on October 8, 2014. This test uses embedded bolts (M12, SUS304, head diameter φ30 mm, head thickness 5 mm, shaft length 130 mm), and the head of this embedded bolt is 450 mm × 450 mm × 200 mm, compressive strength 21 N / mm. ^It is installed in the second non-through hole formed in the concrete test body of No. 2, and the first non-through hole and the second non-through hole are filled with shrink mortar and the one not filled with shrink mortar is the maximum. The tensile load value was measured. The number of samples is 3 for each sample. A first non-through hole having a large diameter of 32 mm and a second non-through hole having a small diameter of 14 mm communicating with the first non-through hole (a distance of 40 mm between the two holes) are formed in the central portion of the concrete specimen. . The tester used was a 500 kN class universal tensile tester (AG-500 kN Xplus) manufactured by Shimadzu Corporation (maximum load: 500 kN, tensile displacement: 1160 mm, maximum test speed: 50 mm / min).

  As a test method, a concrete test body with embedded bolts is fixed on the test stand of the testing machine, and the measurement is started by sandwiching the threaded part of the embedded bolt with the chuck of the tensile tester. Alternatively, the test is terminated when the embedded bolt is broken, and the maximum tensile load value is measured.

  Table 1 shows samples 1-1 to 1-7 in which the shrinkage mortar is filled in the second non-through hole in which the embedded bolt is installed and the first non-through hole. When the shrinkage mortar is not filled in the second non-through hole and the first non-through hole in which the embedded bolt is installed, the head of the embedded bolt is deformed at a tensile load value much lower than Table 1, An internal collapse of the non-through hole occurred. As can be seen from Table 1, in Samples 1-1 to 1-7, which are examples of the present invention, sufficiently excellent maximum tensile load values are obtained.

  The above-described embodiments and examples are all illustrative and do not limit the present invention, and the present invention can be implemented in various other modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

1, 1 ', 10 Covering concrete layer 2a, 2b, 2', 11 Keyhole-shaped hole 3, 3 ', 12 Embedded bolt 4, 4', 16 First non-through hole (bolt insertion hole)
5, 5 ', 17 Second non-through hole (bolt installation hole)
12a Head part 12b Shaft part 13 Washer 14 Nut 15 Filler 16a Bottom 18 First lateral communication path 19 Second lateral communication path

Claims (6)

A plurality of keyhole holes drilled in the concrete layer where the embedded bolts are to be installed, and a plurality of embedded bolts whose heads are inserted and fixed in the plurality of keyhole holes;
Each keyhole-shaped hole communicates with the first non-through hole having a diameter larger than the diameter of the head of the embedded bolt, and from the diameter of the head of the embedded bolt. A second non-through hole having a diameter smaller than that of the shaft portion of the embedded bolt and in which the head portion of the embedded bolt is disposed,
When the concrete layer is a ceiling surface concrete layer that is a concrete layer of a ceiling surface , at least a part of the plurality of keyhole-shaped holes has the second non-penetrating hole from the center of the first non-penetrating hole. A mounting structure for a plurality of embedded bolts, wherein the ceiling concrete layer is perforated so that directions toward the center of the hole are different from each other. At least some of the plurality of keyhole-shaped holes have the ceiling surface such that directions from the center of the first non-through hole to the center of the second non-through hole are opposite to each other. The mounting structure for a plurality of embedded bolts according to claim 1, wherein the structure is drilled in a concrete layer. When the concrete layer is a side wall surface or a slant wall surface concrete layer that is a side wall surface or a slant wall surface concrete layer , at least a part of the plurality of key hole holes is formed from the center of the first non-through hole. 2. The side wall surface or the inclined wall surface concrete layer is perforated so that a direction to the center of the second non-through hole is a downward direction on the side wall surface or the inclined wall surface. 2. A structure for mounting a plurality of embedded bolts according to 2.   Each of the keyhole-shaped holes has a width substantially equal to the diameter of the second non-through hole, and the second non-through hole and the first non-through hole extend over substantially the entire length of the second non-through hole. In a predetermined depth range of the second non-through hole and a first lateral communication path that communicates with each other, a width substantially equal to or slightly larger than the diameter of the first non-through hole The second non-through hole and the second non-through hole are in communication with each other, and the head of the embedded bolt is connected to the second non-through hole. The mounting structure for a plurality of embedded bolts according to any one of claims 1 to 3, wherein the mounting structure is configured to be disposed in the second lateral communication path.   Filler in the first non-through hole, the second non-through hole, the first lateral communication path, and the gap between the second lateral communication path and the embedded bolt of each keyhole-shaped hole The structure for mounting a plurality of embedded bolts according to claim 4, wherein:   The mounting structure for a plurality of embedded bolts according to any one of claims 1 to 5, wherein the first non-through hole is deeper than the depth of the second non-through hole.

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